Work feeding mechanism for sewing machines



Oct. 15, 1946.

R. BECKER WORK FEEDING MECHANISM FOR SEWING MACHINES Filed' May 22, 1945 s. Sheets-Sheet 1 oooooo ooeoooo R. BECKER WORK FEEDING MECHANISM FOR SEWING MACHINES Filed May 22, 1945 3 Sheets-Sheet 2 awn 0a. 15, 1946. R, BECKER 2,409,242

WORK FEEDING MECHANISM FOR SEWING MACHINES Patented Get. 15, 1946 WORK FEEDING MECHANISM FOR SEWING MACHINES Rudolph Becker,

to The Singer North Plainfield, N. J., assignor Manufacturing Company, Elizabeth, N. J a corporation of New Jersey Application May 22, 1945, Serial No. 595,099

15 Claims.

This invention relates to sewing machines, and more particularly to work-feeding mechanisms for sewing machines of the heavy duty, multiple needle type.

The invention has as a primary object to provide an unusually strong work-feeding mechanism, for heavy duty sewing machines, which is positive in its action and rigid in construction so that it will not be distorted under the heavy stresses to which it is subjected during operation of the machine,

Another object of the invention is to provide a heavy duty feeding mechanism for sewing machines in which both the power to lift the workfeeding element and the power to give it its workadvancing movement are each applied at a plurality of spaced points, thereby avoiding distortion of the parts when under heavy stresses.

A further object of the invention is to provide, in a dual actuated work-feeding mechanism, means for simultaneously and equally adjusting both of the feed actuating means.

Still another object of the invention is to provide, in a sewing machine work-feeding mechanism, improved means for leveling or tilting the feed-dog as may be desired.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings,

Fig. 1 is a front elevation of a heavy duty sewing machine embodying the present invention.

Fig. 2 is a horizontal sectional view taken substantially on the line 2-2 of Fig. 1, with the various cover-plates omitted.

Fig. 3 is a transverse vertical sectional view taken substantially on the line 3-3 of Fig. 2.

Fig. 4 is a transverse sectional view taken substantially on the line 4-4 of Fig. 2.

Fig. 5 is a view similar to Fig. 3, but with certain parts omitted and showing, in full and dotted lines, parts of the feeding mechanism in two positions of adjustment.

Referring more specifically to the drawings, the invention is disclosed as embodied in a sewing machine having a frame comprising a pan-like bed or base I, a standard 2 and an overhanging bracket-arm 3 terminating in a bracket-arm head 4. Journaled in bearings 5, lengthwise of the bracket-arm, is a main or arm shaft 6 carrying, at its rear end, a combined belt and hand wheel I through which the shaft 6 is driven from any suitable source of power,

' Mounted in the head 4, for endwise reciprocation, are two needle-bars 8, each having fixedly secured to its lower end, a needle carrying block 9. Secured in and extending through the blocks 9 are two horizontally disposed rods l0 upon which are adjustably secured a plurality of needle-carrying blocks ll each similar to the blocks 9. Each of the blocks 9 and I I is adapted to carry a needle N, only three of which are shown. Any suitable number of blocks ll may be mounted upon the rods ID and, by adjusting them along the rods and securing them thereto, any desired spacing of the needles and consequently any desired spacing of the seams formed thereby may be obtained.

Cooperating with each of the needles, in the formation of stitches, is a chain stitch looper L, also of which only three are shown. These loopers may be of the thread-carrying variety or the non-thread-carrying variety dependent upon whether a two thread or single thread chainstitch seam is desired. The loopers L are secured in a looper-carrier l2 in proper position to cooperate with its complemental needle. The looper-carrier, and the loopers carried thereby, are given oscillatory and orbital movement from a rotary feedand looper-actuating shaft [3, journaled in bearings H3 in the base, through mechanism designated generally as w. Inasmuch as the looper actuating mechanism forms no part of the present invention, detailed illustration and description thereof is deemed unnecessary.

The shaft I3 is rotated from the main shaft 6 through the medium of a one-to-one pulley and clip-belt drive, located in a vertically disposed cavity 2 in the standard 2, and comprising a grooved pulley 6 on the shaft 6, a similar pulley 13* on the shaft l3 and a clip-belt 6* connecting I those pulleys,

which operate the sections of a feed-dog l6 of a lower four-motioned work-feeding mechanism hereinafter to be described. During the time that the feed-dog is below the upper face of the throat-plate, the work is held on the throat-plate by two presser-feet I! each secured upon the lower end of a spring-depressed presser-bar mounted in the head 4. When the feed-dogs are above the upper surface of the throat-plate, during a Work-feeding movement, the presser-feet yieldingly bear upon the work and therefore cooperate with the feed-dog in the feeding of the work.

The overall spacing of the outside needles is relatively great and, as the pre'sser-feet and feed dog must be greater in width than the overall spacing of the needles, it follows that the presserfeet and feed-dog also are of considerable width. This, together with the fact that the machine is designed for use on heavy materials, necessitates that a relatively heavy spring pressure be applied to the presser-feet to insure proper feeding of the work. During the feeding stroke this pressure is transmitted directly to the feed-dog and thereby to the feed-bar or frame which carries the feed-dog.

The present improved work-feeding mechanism includes the feed-dog I6 and a horizontally disposed substantially U-shaped feed-frame I8 comprising two slide-bars I9, -to the forward ends of which the feed-dog I6 is secured, and a crossbar to which the rear ends of the'slide-bars I9 are connected. The feed-frame I8 is slidingly mounted On two horizontally disposed guide-bars -2| pivotally connected, at 22, to the bed of the machine. The feed-frame is reciprocated on its guide-bars by two independent drives comprising two aligned rock-shafts 23 and 24 journaled, respectively, in bearings 25 and 26, 26 in the machine base.

' Th rock-shaft 24 is oscillated from a feeddrive eccentric 3| on the rotary feed and looper actuating shaft I3 through the medium of a pitman 32 having one end surrounding the eccentric -3| and its other end connected, at 29, to the upper endofa rock-arm 33 fixed to the shaft 24. (See Figs. 2 and 4.) The rock-shaft'23 is similarly oscillated from an eccentric 21 on the shaft I3 through a pitman 28 connecting the eccentric with the upper endof 'a rock-arm 30 secured upon the shaft 23.

The'eccentri-cs 27, 3|, pitmans 28, 32 and the rock-arms 39, 33 are identical and therefore the rock-shafts 23, 24 are oscillated synchronously from the shaft I 3.

Each rock-shaft 23, 24 is provided with a feed rocker in the form of an upstanding segmental arm 34 having a projecting rib 34 upon "each of which is adjustably fitted a grooved slide-block 35 adapted to be held in adjusted position by a set screw 36 threaded through the block 35 and bearing against the side of the rib 34. Each slide-block 35 carries a laterally projecting stud 35 which fits into a bore 37 formed in the horizontal tubular end portion 3! of a link 31, the other end portion of which is pivotally connected to the feed-frame I3. A coil spring 31*, fitted within the bore 31, bears against the ends of the studs 35 and urges the slide-blocks 35 into r frictional contact with the ribs 34 of the feedrockers 34, when the screws 36 are released. For convenience of manufacture, and to insure simultaneous adjustment, the link connections between the studs ably combined into a single link 31, forked as at 37 and providing sleeves 37 pivotally connected, at spaced points, to the cross-bar 20 of the feed frame. Thus oscillations of the rock-shafts 23, 24 are translated into reciprocations in the feed 3511 and the feed-frame I8 are preferto prevent the blocks from the portions '2 the feed-dog carried thereby will be held frame I8, thereby giving to the feed-dog I6 its feed and return movements. The amplitude of the feed and return movements, and thus the length of stitch produced by the machine, is determined by the setting of the blocks 35 on the ribs 34 nearer to or farther from the axis of oscillation of the shafts 23 and 24; the farther the blocks are adjusted from the axis of oscillation, the greater will be the movement transmitted to the feed-dog, and vice versa. Stopscrews 38 threaded into the upper ends of the ribs 34 have their heads projecting beyond the sides of the ribs and therefore afford abutments being slid off the upper ends of the ribs. Similar stop-screws 39 are provided at the lower ends of the ribs.

Likewise, dual means is provided for giving to the feed-frame, and the feed-dog carried thereby, their rising and falling movements in timed relation with their feed and return strokes. This means comprises a feed-lift rock-shaft 40 journaled in bearings 4| in the bed I; 'apair of feedlift rock-arms 42 having their split hubs secured, by clamp screws 42*, upon the shaft 40; arms 43 secured upon the guide-bars 2|; and links 44 pivotally connected, at 43, to one end of the arms 43 and at their other ends to the rock-arms 42. Thus oscillations of the shaft 46 transmit, at two widely spaced points, rising and falling movements to the guide-bars 2| and thereby to the feed-frame I8 and the feed-dog I6.

oscillatory movements are transmitted to the shaft '43 from an eccentric 45 on the rotary shaft l3. This eccentric is surrounded by a strap 46 carrying a sleeve 41 in which is slidingly fitted a pin 48, projecting from a pinch collar '49, secured upon the'shaft 40.

To enable tilting or leveling of the feed-dog It as may be desired-means is provided for tipping the -feed-frame I8 as indicated in dotted lines in Fig. 5. This is effected by forming each of the guide-bars 2| in two pieces, viz. a cylindrical forward portion 2| on which the feedframe is slidingly mounted and a rearward or anchor portion 2| which is pivotally connected at 22 to the bed of the machine. The portions Zi and 2| are rigidly secured together by a c1ampbolt 50.

When it is desired to vary the angular position-of the feed-dog, the clamp bolts 50 are loosened, after which the feed-frame I8, and the feed-dog carried thereby, may be tipped about the pivotal axis 43 between the arm 43 and link 44; of the guide-rods 2| turning about their pivots 22 and the bolts 50 acting as hinge pins. After the desired adjustment has been effected, the bolts 50 are again tightened to maintain the parts in their adjusted positions.

From the foregoing, it will be perceived that very strong and rigid dual drives are provided between the shaft I3 and the feed-frame I8, for giving to the feed-dog its rising-and-falling and feed-and-return strokes and that, inasmuch as those drives are transmitted to the feed-frame at a plurality of spaced points, the feed-frame and against deflection or distortion by the stresses applied thereto.

It will also be apparent that a sing'lemeans (the simultaneous adjustment of the link 31 on both segmental arms 34) has been provided for simultaneously varying the feed and return stroke transmitted to the feed-dog by the two feeddriving mechanisms.

- It is to'be understood that the above described feeding mechanism may be usedeither separately or in conjunction with a suitable upper feeding mechanism such, for example, as'that disclosed 'in my United States patent, application Serial No. 603,656, filed Ju1y'7, 1945, as an upper and under or clamp feeding mechanism. Portions of said upper feeding mechanism are shown in Figs. 1

drive elements carried by said shaft, two laterally spaced and coaxially journaled feed-rockers, a driving connection between each of said feed- .drive elements and a respectivev one of said feedrockers, and adriving connection between each of said feed-rockers and said feed-frame for imparting work-advancing movements to said feeddog.

2. A work-feeding mechanism for sewing machines comprising afeed-frame, a feed-dog car- ,ried by said feedframe,. a rotary shaft, two feeddrive elements carried by said shaft, two laterally spaced and coaxially journaled feed-rockers, a

driving connection between each of said feeddrive elements and a respective one of said feedfr'ockers, a driving connection between each of said ffeed-rockers'andi said feed fr'am'e for imparting work-advancing movements to saidifeed-dog, and means for simultaneously and equally adjusting the driving connections between both of said feedrockers and said feed-frame, thereby to vary the feeding stroke transmitted to the feed-dog.

3. A work-feeding mechanism for sewing machines comprising a feed-frame, a feed-dog carried by said feed-frame, a rotary shaft, means actuated by said shaft for imparting rising and falling movements to said feed-frame and the feed-dog carried thereby, two feed-drive elements carried by said shaft, two laterally spaced and coaxially journaled feed-rockers, a driving connection between each of said feed-drive elements and a respective one of said feed-rockers, and a single link connection between both of said feed-rockers and said feed-frame for imparting work-advancing movements to said feed-dog.

4. A work-feeding mechanism for sewing machines comprising a feed-frame, a feed-dog carried by said feed-frame, a rotary shaft, two feeddrive elements carried by said shaft, two aligned rock-shafts located rearwardly of said rotary shaft, a driving connection between each of said feed-drive elements and a respective one of said rock-shafts, a rock-arm on each of said rockshafts, and a driving connection between each of said rock-arms and said feed-frame.

5. A work-feeding mechanism for sewing machines comprising a feed-frame, a feed-dog carried by said feed-frame, a rotary shaft located below said feed-frame and extending to opposite sides thereof, a feed-drive element carried by said shaft at each side of said feed-frame, two aligned rock-shafts located rearwardly of said rotary shaft, a driving connection between each of said feed-drive elements and one of said rockshafts, a rock-arm on each of said rock-shafts, and an adjustable driving connection between each of said rock-arms and said feed-frame.

6. A work-feeding mechanism for sewing machines comprising a U-shaped feed-frame, a feeddog carried by said feed-frame, a rotary shaft,

,two feed-drive eccentrics carried by said shaft,

two aligned rock-shafts located rearwardly of said rotary shaft, a driving connection between each ref-said feed-drive elements and one of said rock-shafts,i.a rock-arm on each of said rockshafts, and a single link connection between said rock-arms and said feed-frame.

'1. A work-feeding mechanism for sewingmachines comprising a U-shaped feed-frame, a feeddog carried bysaid feed-frame, a rotary shaft locatedbelow said feed-frame and extending to opposite sides thereof, a feed-drive eccentric car,- ried by said shaft at each side of said feed-frame, two. aligned rock-shafts located rearwardly of said rotary shaft, a driving connection between each of said feed-drive eccentrics and one of said rock-shafts, a segmental rock-arm on each of said rock-shafts, and a link pivotally connected to said feed-frame and adjustably connected to both of said rock-arms.

8. A work-feeding mechanism for sewingmachines comprising a U-shaped feed-frame including spaced slide-bars and a cross-bar connecting said slide bars, afeed-dog carried by the free end of said feed-frame, a rotary shaft located below said feed-frame and extending to opposite sides thereof, a feed-driv element carried by said shaft at each side of said feed-frame, two aligned rock-shafts located rearwardly of said rotary shaft, a drivi g connection between each of said feed-drive elements and one of said rockshafts, a segmental rock-arm on each of said rock-shafts, a slide-block adjustably mounted on each of .said rock-arms, a link pivotally connected "at one end to thecross bar of said feed-frame and at its opposite end to said slide blocks, and means to raise and lower said feed-frame and the feed-dog carried thereby.

9. In a sewing machine having a base and a rotary shaft journaled in said base; a pair of horizontally spaced guide-bars secured at one end to said base, a feed-frame slidingly mounted on said guide-bars, a feed-dog carried by said feedframe, two aligned rock-shafts journaled in said base rearwardly of said rotary shaft, individual means for oscillating each of said rock-shafts from said rotary shaft, a rock-arm on each of said rock-shafts, and a driving connection from each of said rock-arms to said feed-frame to reciprocate said frame on said guide-bars.

10. In a sewing machine having a base and a rotary shaft journaled in said base; a pair of spaced guide-bars secured at one end to said base, a feed-frame slidingly mounted on said guidebars, a feed-dog carried by said feed-frame, two aligned rock-shafts journaled in said base, individual means for oscillating each of said rockshafts from said rotary shaft, and means actuated by each of said rock-shafts for reciprocating said feed-frame on said guide-bars.

11. In a sewing machine having a base and a rotary shaft journaled in said base; a pair of spaced guide-bars pivotally secured at one end to said base, a feed-frame slidingly mounted on said guide-bars, a feed-dog carried by said feed-frame, two aligned rock-shafts journaled in said base, individual means for oscillating each of said rockshaft from said rotary shaft, means actuated by each of said rock-shafts for reciprocating said feed-frame on said guide-bars, and means to adjust the position of said guide-bars thereby to vary the position of said feed-frame and feed-dog.

12. In a sewing machine having a frame including a Work-support and a rotary shaft journaled below said work-support; a guide-bar com- L prising two adjustably connected parts of which one part is journaled on a fixed pivot carried by and feed-dog relative to the work-support.

13. In a sewing machine having a base'and a rotary shaft journaled in said base; a pairflof spaced guide-bars pivotally secured at one end to said base, each of said guide bars including an anchor section and a slide section and-means securing said sections together, a feed-frame "slidingly mounted on the slide sections of said guide-bars, afeed-dogcarried by said feed-frame, two aligned rock-shafts journaled in said base, individual means for oscillating each 'o'fisa'id rockshafts from said rotary shaft, means actuated by each of said rock-shafts forreciprocating said feed-frame on said 'guide-bars,and means to vary the angle betweenthe two section of each guidebar thereby to vary the position of said feedframe and feed-dog relative to a horizontalplane.

1 1. 'In a sewing machine having a base, -a rotary shaft journaled in said base, an oscillatory shaft journaled in said base parallel to said rotary shaft, and means for actuating said oscillatory shaft from said rotary sha'ft'; a 'slidingly mounted feed-frame overlying sa'id shafts, a feed-dog carried by said feed-frame, two aligned'rock-shafts j'ournaled in -said base, indivi'dual meansfor oscillating each of said rock-shafts from said rotary shaft, a rock-arm on each or said rock-shafts,

a driving connection between each of said rockarms and said feed-frame to reciprocate said feed-frame and the feed-dog'carriedthereby, and individual 'means actuated by said oscillatory shaftand connected with said feed-frame adjacent opposite sides thereof to give to said feedframe rising and falling movements.

15. In a sewing machine having a base, a rotary shaft journaled therein, an oscillatory shaft journaled in said base parallel to said'rotary shaft, a pair of rock-arms on said oscillatory shaft, and means for actuating said oscillatory shaft from said rotary shaft; a pair of parallel guide-bars each having one end pivoted to-said base, a U- shaped feed-frame overlying said shafts and slidingly mounted on said guide-bars, a feed-dog carried by the free end of said feed-frame, two aligned rock-shafts journaled in said base, individual means for oscillating each of said rockshafts from said rotary shaft, a rock-arm on each of said rock-shafts, a driving connection 'between each of said rock-arms and said feedframe to reciprocate said feed-frame and the feed-dog carried thereby, Jinks pivotally connecting said .pair of rock-arms with said feed-frame to give to said feed-frame rising and falling movements, and means for adjusting said feed-frame angularly about the pivotal connection between said links and said feed-frame to vary the position of said feed-dog.

RUDOLPH BECKER. 

